Track shoe connector

ABSTRACT

A track end connector with a simple single bolt means to secure the pins from adjacent track shoes and hold the pins in a relationship so the track shoes have the desired angular orientation relative to each other.

GOVERNMENT INTEREST

[0001] The invention described here may be made, used and licensed by and for governmental purposes without paying me any royalty.

BACKGROUND OF THE INVENTION

[0002] In one aspect this invention relates to tracked vehicles. In yet a further aspect this invention relates to the construction of endless tracks.

[0003] Track laying vehicles such as tanks ride on an endless track structure. Such tracks consist of a series of track shoes having pins that extend outward perpendicularly to the track shoe. Adjacent track shoes are held in a spaced array by means of end connectors that engage the pins extending from the track shoe. Several methods have been proposed for holding the pins in the end connector. The most commonly used technique is the use of a bolt that engages a wedge that in turn engages a milled portion of the pin in within the track shoe. Such connectors have a problem in that the bolt tends to loosen as the track is used requiring frequent re tightening of the bolt. The frequent need to tighten and retorque the bolts sometimes results in failure of the bolt heads requiring extensive work to repair the track strand.

[0004] It would be desirable to have an end connector that is simpler in construction. A further desirable feature would be a connector that will visually show when the bolt is beginning to loosen so it can be easily retorqued.

SUMMARY OF THE INVENTION

[0005] The end connector system of this invention is a simplified system used for joining adjacent sections of double pin track shoes to form an endless track strand. The system uses an end connector with a connector body having two spaced, parallel track pin apertures. The apertures are adapted to receive and hold the pins that extend outward from the track shoe. Adjoining track shoes pins are thus held in a parallel relationship and the track shoes will form a continuous strand of track, which can be extended to the desired length and then closed to form an endless loop. The end connector body has a shaped bore disposed orthogonally to and located between the pin apertures, with an opening on one surface of the connector body; the shaped bore having a portion which overlaps into the track pin apertures. The shaped bore has a threaded section distal the opening in the connector body surface.

[0006] A bolt having a threaded portion complimentary to and adapted to engage the threaded portion of the bore is used to hold the track shoe pins. The threaded portion is sized so it will pass through the bore in the end connector without engaging the pins from the track shoe when they are disposed in the apertures. The bolt has a land section juxtaposed the threaded section the land section being of a diameter which will substantially fill the volume of the shaped bore which is common with track pin apertures. When the bolt is fully seated in the bore, the land section is adapted to engage a cam surface formed on the pins of the track shoes as the bolt is tightened to hold the pins within the connector body.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In the accompanying drawing:

[0008]FIG. 1 is a side view in partial section of one end connector of this invention;

[0009]FIG. 2 is a view of the end connector of FIG. 1 with the bolt partially inserted;

[0010]FIG. 3 is a view of the end connector of FIG. 1 with the bolt fully tightened; and

[0011]FIG. 4 is a partial view of a pin used with the track shoe with the cam surface exposed.

DETAILED DESCRIPTION

[0012] Referring to the accompanying drawing wherein like numerals refer to like parts, an end connector system for joining adjacent sections of double pin track shoes (not shown) to form an endless track is designated generally 10. The system includes a connector body 12, a bolt 14 that are adapted to engage and hold the substantially cylindrical pins 16 extending from a track shoe only a portion of the pin being shown.

[0013] The end connector body 12, has two spaced, parallel track pin apertures 18, which are parallel to each other and pass entirely through the body of the end connector. The apertures 18 are adapted to receive and hold pins 16 from adjoining track shoes in the track strand and maintain the pins in a spaced parallel relationship. The end connector body 12 has a shaped bore which is formed in the body orthogonal to and located midway between the pin apertures 18, with an opening 22 on one surface of the connector body. The shaped bore 20 has an enlarged portion beginning at the opening on the body surface and extending into the body a portion of the enlarged bore overlapping the track pin apertures 20 to create a shared volume within the connector body 12. The shaped bore 20 has a threaded section 24 distal the opening 22 in the end connector body 12 the threaded section having a diameter smaller than the enlarged bore portion.

[0014] The bolt 14 to be used in the practice of this invention is formed with a threaded portion 26 that is complimentary to and adapted to engage the threaded section 24 of the bore 20. The threaded portion 26 is sized with respect to length and diameter so it will pass through the enlarged portion of bore 20 without engaging the pins 16 from the track shoes while they are disposed in the apertures 18. The threaded portion 26 is also sufficiently long that it can engage the threaded section 24 for at least one turn during installation before contacting any of the remainder of the track connector elements.

[0015] Bolt 14 has a land section 28 juxtaposed the threaded portion 26. The land section 28 has a diameter which will substantially fill the enlarged section of the shaped bore 20 including the volume of the shaped bore which is common to the pin apertures 18 when the bolt 14 is fully seated in the bore. The land section 28 is being adapted to engage a cam surface 30 formed on the pins 16 of the track shoes as the bolt 14 is tightened to hold the pins within the connector body 12 as described below.

[0016] The installation sequence of the end connectors is illustrated taking the FIGS. 1-3 in numerical order. In FIG. 1, the pins 16 from two separate track shoes have been inserted into the apertures 18. As shown in FIG. 1 the cam surface 30 will form a slight angle with the axis of the shaped bore 20. The surfaces will be on the order 5 to 10 degrees with a desired angle of about 7 degrees.

[0017] The bolt 14 will be inserted into the shaped bore 20 until the threaded section 24 engages the threaded portion 24 of the shaped bore and the bolt rotated the complimentary threads drawing the bolt into the shaped bore. At this stage the bolt is firmly anchored but the enlarged section of the bolt is just coming into contact with the cam surface 30. For heavy track shoe applications, such as a tank, the bolt 14 will have about 0.10 to 0.20 inch of engagement to provide proper strength.

[0018] As the bolt 14 is tightened it will reach the final result shown in FIG. 3 where the bolt is completely within the shaped bore and the land section has engaged the cam surface 30. This results in a slight rotation of the pins to align the cam surfaces with the axis of the shaped bore. This will cause the track shoes to have an angle of about 14 degrees with respect to each other. The tightening of the bolt 14 the unthreaded cam surface 28 is drawn further along the essentially parallel cam surface. When fully seated, the bolt 14 resembles a locking pin where nearly all the forces acting on the bolt are normal to the bolt surface. There remains only a moderate force parallel to the bolt surface resulting from the clearance between the parts and gravity. In the fully tightened position the bolt's head is flush with the connector body 12 so it is easy to see if the bolt 14 is loosening as the head will become exposed and proper corrective measures can be promptly applied. It is expected the frictional forces applied to the enlarged section 28 of the bolt 14 by the cam surfaces 30 on the pins 16 will also serve to hold the bolt within the bore 20.

[0019] As shown the bolt 14 has a hexagonal keyway 34 extending through the bolt. This allows the bolt to be accessed from either side to allow tightening or removal should the bolt 14 break during installation or repair. This solves the problem of prior art track structures where the breakage of a bolt head would require drilling out the remaining bolt to separate track elements.

[0020] Various alterations and modifications will become apparent to those skilled in the art without departing from the scope and spirit of this invention and it is understood this invention is limited only by the following claims. 

What is claimed is:
 1. An end connector system for joining adjacent sections of double pin track shoes to form an endless track: a connector body having two spaced, parallel track pin apertures, the apertures being adapted to receive and hold pins from adjoining track shoes in a spaced parallel relationship, a shaped bore disposed orthogonally to and located between the pin apertures, with an opening on the surface of the connector body, the shaped bore having a portion which overlaps into the track pin apertures, the shaped bore having a threaded section distal the opening in the connector body surface; and a bolt having a threaded portion complimentary to and adapted to engage the threaded section of the bore the threaded portion being sized so as to pass through the bore without engaging the pins from the track shoes while they are disposed in the apertures, a land section juxtaposed the threaded section the land section being of a diameter which will substantially fill the volume of the shaped bore which is common with the pin apertures, when the bolt is fully seated in the bore, the land section being adapted to engage a cam surface formed on the pins of the track shoes as the bolt is tightened to hold the pins within the connector body.
 2. The track end connector system of claim 1 where the bolt has a shaped keyway formed through the bolt to allow rotational force to be applied to the bolt from either end. 